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Work with Chinese CTC IMS network

Work with Chinese CTC IMS network

Yesterday, we helped a Chinese customer to deploy MSS to work with CTC IMS network. In this scenario, CTC IMS network has ZTE soft-switch (according to User-Agent header in SIP messages) , we need be careful to cooperate with it.

Since CTC provides user name and password for authorization, we configure “external line” in MSS to do that. Following sections will illustrate some key points.

Authorization user name

By default, we often use “External line (account)” as authorization user name, but ZTE softswitch requires full URI format, so we need configure “The authorization ID should include address information” in external line. Please refer to following figure for more details.

Authorization user name
Authorization user name

For example, if this item is selected, the authorization name will be “+8612345678@gd.ctcims.cn” according to above figure.

If it is not full format, IMS network will return “403 Forbidden” messages to reject it. In fact, we think it is a bug in ZTE softswitch since there is “realm” and “domain” parameters in SIP authorization header. No matter the user name is full format or not, the device should pass it according to successful authorization itself.

Anyway, if you have same problem to cooperate with other IMS networks, please pay attention to it and configure such item to take a try.

Proxy

In Chinese CTC-IMS network, its “SIP server” is logic domain, not a real SIP device and cannot be visited. In above scenario, “gd.ctcims.cn” is its domain, not its real address. SIP messages should be routed to another device (we think it is a SBC or proxy), so we need configure “Via” address in MSS external line configuration. Please refer to following figure.

SIP proxy in IMS
SIP proxy in IMS
miniSIPServer V14

miniSIPServer V14

miniSIPServer is upgraded to V14.2 now. With latest versions, following key features are included:

(1) For raspberry Pi. As we know, raspberry Pi is a very small PC run on Debian system, MSS can work on this hardware now. It is very helpful for some small business who dont want to maintain a PC hardware and save many cost.

(2) Provide open API. MSS can start web server and provide open HTTP API . 3rd parties can use this interface to intergrate with their own system. At this time, open API set can support: query MSS version; configure or query details of local users.

(3) Routing group. It is a very helpful feature for customers who have lots of external lines or SIP trunks. They can manage these lines or trunks into different groups for different users or for different calls. The workload of group is in round-robin policy.

Hope you can enjoy our new versions! If you have any questions or suggestions, please feel free to contact us. We are always here for you.